As a rule, tampons consist of mixtures of cotton and rayon staple wadding in rolled form. They are produced in different sizes, that is, quantities of wadding material, and consequently also have different absorption capacities. What determines the quality of a menstruation tampon is its absorbency.
There are substances which in admixtures with the wadding greatly improve the absorption capacity of the fiber. These substances are hydrophilic agents and include, for example, carboxymethyl cellulose (CMC). Similar effects can be obtained also with other substances which have special sorptive properties, such as certain hydrophilic polymers or foamed polyurethanes. By sprinkling such substances, such as carboxymethyl cellulose fibers (CMC fibers) onto the wadding surface, the absorption capacity of the entire tampon can be increased appreciably. For example, 5% admixtures result in 15% to 20% improvements of the absorption capacity.
A tampon with a fiber admixture modified to be more hydrophilic is known, for example, from German Published Application DOS No. 2,614,122. The fiber admixture is here distributed uniformly over the entire tampon. While the tampon has a very good absorbency, it does not have an absorption reserve when fluid occurs suddenly.
To form such zones, which serve to improve the rate of absorption and absorption capacity for the purpose of preventing the bleeding through past the tampon, amplified zones of wadding have heretofore been used. It was found, however, that with appreciable zone-wise amplification of the amount of wadding, overpressures in the tampon are inevitable, whereby the absorption capacity is greatly reduced.